The invention discloses a nitrogen and phosphor-doped biomass carbon material synthetic method and an application of the biomass carbon material in a microbiological fuel cell cathode. The method comprises the following steps: taking cellular biomass as a substrate, after pretreatment, respectively sintering the cellular biomass to a carbon material under inert atmosphere at the temperatures of 600 DEG C, 700 DEG C and 800 DEG C, taking cellular as a carbon source, respectively taking melamine and 1,2-vinyl diphosphate as a nitrogen source and a phosphorus source, mixing the raw materials according to a certain proportion for doping, performing a hydrothermal reaction for 5 h in a reaction vessel at the temperature of 100 DEG C, and successfully preparing a nitrogen and phosphor-doped carbon N/P-C semispherical porous microbe cathode material. The method has the advantages that the microbe cathode oxygen reduction catalytic activity is increased, the biomass carbon material has more excellent cycle stability, catalysis electrode charge transfer impedance is reduced, the electron transfer rate is accelerated, a cathode oxygen reduction reaction is promoted, and the provided electric energy can supplies the requirements of other fields.